2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Sleep habits, insomnia, and daytime sleepiness in a large and healthy community-based sample of New Zealanders

STUDY OBJECTIVES

To determine the relationship between sleep complaints, primary insomnia, excessive daytime sleepiness, and lifestyle factors in a large community-based sample.

DESIGN

Cross-sectional study.

SETTING

Blood donor sites in New Zealand.

PATIENTS OR PARTICIPANTS

22,389 individuals aged 16-84 years volunteering to donate blood.

INTERVENTIONS

N/A.

MEASUREMENTS

A comprehensive self-administered questionnaire including personal demographics and validated questions assessing sleep disorders (snoring, apnea), sleep complaints (sleep quantity, sleep dissatisfaction), insomnia symptoms, excessive daytime sleepiness, mood, and lifestyle factors such as work patterns, smoking, alcohol, and illicit substance use. Additionally, direct measurements of height and weight were obtained.

RESULTS

One in three participants report < 7-8 h sleep, 5 or more nights per week, and 60% would like more sleep. Almost half the participants (45%) report suffering the symptoms of insomnia at least once per week, with one in 5 meeting more stringent criteria for primary insomnia. Excessive daytime sleepiness (evident in 9% of this large, predominantly healthy sample) was associated with insomnia (odds ratio [OR] 1.75, 95% confidence interval [CI] 1.50 to 2.05), depression (OR 2.01, CI 1.74 to 2.32), and sleep disordered breathing (OR 1.92, CI 1.59 to 2.32). Long work hours, alcohol dependence, and rotating work shifts also increase the risk of daytime sleepiness.

CONCLUSIONS

Even in this relatively young, healthy, non-clinical sample, sleep complaints and primary insomnia with subsequent excess daytime sleepiness were common. There were clear associations between many personal and lifestyle factors-such as depression, long work hours, alcohol dependence, and rotating shift work-and sleep problems or excessive daytime sleepiness.

Sleep, blood pressure and obesity in 22,389 New Zealanders

AIM

To determine the relationship of sleep disorders with blood pressure and obesity in a large, relatively healthy, community-based cohort.

METHODS

A cross-sectional study was undertaken using data from 22,389 volunteer blood donors in New Zealand aged 16-84 years. Height, weight, neck circumference and blood pressure were measured directly, and data on sleep and other factors were ascertained using a validated self-administered questionnaire.

RESULTS

Even in a relatively young, non-clinical cohort, lack of sleep (34%), snoring (33%), high blood pressure (20%) and obesity (19%) are common. After adjusting for relevant confounders, participants at high risk of sleep apnoea had double the odds of having high blood pressure but only in participants over 40 years. Very low and high quantities of sleep are also associated with high blood pressure. Even after controlling for neck circumference, self-reported sleep apnoea, sleep dissatisfaction and low amounts of sleep are associated with a higher body mass index.

CONCLUSIONS

Obesity and hypertension have significant associations with a variety of sleep disorders, even in those less than 40 years of age and after adjusting for a wide range of potential confounders.

Polysomnography in Australia--trends in provision

OBJECTIVES

To describe the growth in the use of state-funded (Medicare) polysomnography (PSG) in Australia since 1990 and to compare PSG growth to other common diagnostic procedures and growth in total Medicare payments.

METHODS

Interrogation of online database of historical census-level data routinely collected by Medicare.

RESULTS

There has been a steady rise in the number of PSGs performed in Australia since 1990; the growth has been faster than overall Medicare-spending growth and faster than growth in comparable diagnostic procedures. However, there are marked interstate differences in growth. Per capita data, available only for 1995 to 2004, shows that nationwide PSG provision has risen from 123 to 308 per 100,000 people enrolled in Medicare.

CONCLUSIONS

The provision of PSG in Australia has been growing steadily since publicly funded reimbursement began in 1990. This growth has been faster than the overall population growth and faster than the growth in Medicare funding for other diagnostic procedures and classes of medical interventions. However, the provision of PSG might be expected to continue to increase because the per capita provision (308 per 100,000) is still less than recent estimates from Canada and the United States (370.4 and 427.0 per 100,000, respectively).

Ventilatory changes in heat-stressed humans with spinal-cord injury

STUDY DESIGN

Single trial using matched subjects under tightly-controlled experimental conditions.

OBJECTIVE

Humans with spinal-cord injury have a reduced ability to dissipate heat. The current project examined the possibility that, in such people, an elevated ventilatory response (panting) may act as a supplementary avenue for heat loss.

SETTING

Australia, New South Wales.

METHODS

Breathing frequency was measured during a resting heat exposure (<or=2 h) in 10 subjects with spinal-cord injury (C4-L5), and in 10 mass- and age-matched, able-bodied subjects.

RESULTS

Subjects with spinal-cord injury displayed a ventilatory sensitivity, relative to mean body temperature change (2.4 breaths/min/ degrees C +/-0.9), more than twice that of able-bodied subjects (1.1 breaths/min/ degrees C +/-0.6; P=0.042). Furthermore, the higher the level of spinal-cord injury, the greater was the ventilatory response (r2=0.51, P=0.048).

CONCLUSION

While these ventilatory changes were apparently thermally mediated, they did not represent a true panting response, nor did the increased breathing frequency confer a physiologically significant thermoregulatory benefit that may help compensate for the loss of sympathetic flow to eccrine sweat glands and cutaneous blood vessels in people with spinal-cord injury.

Respiratory events and periodic breathing in cyclists sleeping at 2,650-m simulated altitude

We examined the initial effect of sleeping at a simulated moderate altitude of 2,650 m on the frequency of apneas and hypopneas, as well as on the heart rate and blood oxygen saturation from pulse oximetry (SpO2) during rapid eye movement (REM) and non-rapid eye movement (NREM) sleep of 17 trained cyclists. Pulse oximetry revealed that sleeping at simulated altitude significantly increased heart rate (3 +/- 1 beats/min; means +/- SE) and decreased SpO2 (-6 +/- 1%) compared with baseline data collected near sea level. In response to simulated altitude, 15 of the 17 subjects increased the combined frequency of apneas plus hypopneas from baseline levels. On exposure to simulated altitude, the increase in apnea was significant from baseline for both sleep states (2.0 +/- 1.3 events/h for REM, 9.9 +/- 6.2 events/h for NREM), but the difference between the two states was not significantly different. Hypopnea frequency was significantly elevated from baseline to simulated altitude exposure in both sleep states, and under hypoxic conditions it was greater in REM than in NREM sleep (7.9 +/- 1.8 vs. 4.2 +/- 1.3 events/h, respectively). Periodic breathing episodes during sleep were identified in four subjects, making this the first study to show periodic breathing in healthy adults at a level of hypoxia equivalent to 2,650-m altitude. These results indicate that simulated moderate hypoxia of a level typically chosen by coaches and elite athletes for simulated altitude programs can cause substantial respiratory events during sleep.

Whole-body pre-cooling does not alter human muscle metabolism during sub-maximal exercise in the heat

Muscle metabolism was investigated in seven men during two 35 min cycling trials at 60% peak oxygen uptake, at 35 degrees C and 50% relative humidity. On one occasion, exercise was preceded by whole-body cooling achieved by immersion in water during a reduction in temperature from 29 to 24 degrees C, and, for the other trial, by immersion in water at a thermoneutral temperature (control, 34.8 degrees C). Pre-cooling did not alter oxygen uptake during exercise (P > 0.05), whilst the change in cardiac frequency and body mass both tended to be lower following pre-cooling (0.05 < P < 0.10). When averaged over the exercise period, muscle and oesophageal temperatures after pre-cooling were reduced by 1.5 and 0.6 degrees C respectively, compared with control (P < 0.05). Pre-cooling had a limited effect on muscle metabolism, with no differences between the two conditions in muscle glycogen, triglyceride, adenosine triphosphate, creatine phosphate, creatine or lactate contents at rest, or following exercise. These data indicate that whole-body pre-cooling does not alter muscle metabolism during submaximal exercise in the heat. It is more likely that thermoregulatory and cardiovascular strain are reduced, through lower muscle and core temperatures.